Method and apparatus for preparing substances for optical analysis

ABSTRACT

A solid matter collection apparatus and a method for collecting solid matter in a fluid. The apparatus includes a collection site that collects the solid matter at a predetermined density and location that is suitable for exposing the solid matter to electromagnetic spectroscopy.

TECHNICAL FIELD OF THE INVENTION

The present invention is directed to an apparatus and method forcollecting and analyzing matter in a fluid.

BACKGROUND OF THE INVENTION

In a wide variety of technologies, the ability and/or facility inseparating matter, typically particulate matter, from a fluid is acritical component in the ability to test for the presence of substancesin the fluid. For example, laboratories are now able to use infra-redspectroscopy to determine the presence of cancer cells, but the utilityof this technique is hampered by the difficulty in sample preparation.Too often, interference associated with sample preparation obscures thetarget cells to such a degree that the process is not sufficientlyreliable, or too costly.

A similar scenario applies to many other fields which involve detectionand/or diagnosis, including environmental testing, radiation research,cancer screening, cytological examination, microbiological testing, andhazardous waste contamination, to name just a few.

In all of these endeavors, a limiting factor in the sample preparationprotocol is adequately separating solid matter from its fluid carrier(e.g., a variety of fluids, such as physiological, biological andenvironmental), and in easily and efficiently collecting andconcentration the solid matter in a form readily accessible toelectromagnetic radiation. For example, it has been reported that infrared technology can be used to differentiate between malignant cells andnormal cells. The cells exhibit a characteristic absorbance wavelengthwhich may be used to identify the presence and type of cell and itsquantity. The sample preparation processes involves painstakinglyisolating the target cells from tissue or body fluids, then passing aninfra-red beam through a support which holds the cell sample. In atypical process, the cells must be collected and smeared on a support,such as a microscope slide. The collection and transfer requires somedegree of skill, and even then, a cell smear may not be suitable foranalysis using infra red technology.

Diagnostic microbiology and/or cytology, particularly in the area ofclinical pathology, bases diagnoses on a microscopic examination ofcells and other microscopic analyses. The accuracy of the diagnosis andthe preparation of optimally interpretable specimens typically dependsupon adequate sample preparation.

The present invention is based in part on the relatively new developmentof using electromagnetic radiation, such as infrared radiation, tocharacterize matter. For example, an infra red beam may be passedthrough some type of support which holds solid matter, such as cells, ina predetermined position. By passing the beam through the solid matter,the solid matter absorbs a characteristic wavelength within the beam;this absorbance can be measured. This measurement, and thecharacteristic absorbance pattern may be used to identify the type andquantity of the solid matter present in the sample and its molecularmake-up or composition.

As noted above, however, any electromagnetic protocol is limited by themanner in which the sample is prepared. The present invention providesan easy, quick, cost efficient, reproducible, and superior process andapparatus for collecting the solid matter suitable for analysis usingelectromagnetic radiation.

The present invention provides a stark contrast to the various samplepreparation techniques typically used. In the cast film method, thesample is dissolved in a solvent, the solution is added dropwise to aninfra red window material (KBr or Csl), and the solution is allowed toevaporate, forming a thin film on the window material. In some cases,the thin film must be removed from the window material and placed on aninert solid support prior to exposure to infra red radiation.

In the hot press film technique, polymeric samples are carefully meltedbetween two infra red salt plates (KBr or Csl), carefully pressing oneof the plates against the other until a thin film is formed. In asimilar technique, a liquid smear is formed by pressing a viscous fluidsample until a capillary film is produced.

In the potassium bromide pellet technique, the sample is ground to aparticle size of about one micron, the sample is mixed with infra redgrade KBr (carefully, to insure homogeneity), and the powder mixture ispelletized using high pressure.

Low concentration samples may also be prepared using pyrolysis, e.g.,forming a dry distillation of a liquid distillate.

It should be readily apparent that for each of these infra red analysissample preparation protocols, significant manipulation of the sample isrequired. Furthermore, the sample must be transferred to a solid supportor window material (KBr, Csl, glass, aluminum foil, or a mercurysurface), materials which sometimes interfere with the sample absorbancepattern.

SUMMARY OF THE INVENTION

The present invention relates to an apparatus and method for collectingmatter for detection, analysis, quantification, and/or visualizationusing electromagnetic radiation. The devices and methods of the presentinvention are particularly suitable for separating matter frombiological, physiological, and environmental fluids and analyzing theparticulate matter with infra red radiation. For example, a deviceaccording to the invention prepares matter in the sample for analysis,in combination with facilitating the actual application ofelectromagnetic radiation to the collected matter. Thus, matter isreadily analyzed and quantified.

Furthermore, sample collection, isolation, preparation, and analysis maybe conducted in a single device. The devices of the present inventionobviate the need for a trained technician to properly prepare a samplesubstrate. Thus, time, expense, and expertise are eliminated or reducedas critical factors in sample preparation protocols.

The devices and methods of the present invention also provide advantagesin sample preparation because they are suitable for use with fresh,untreated cells, unmodified cells, and are particularly designed toprovide a thin, uniform layer of solid matter (up to approximately 40microns or more).

Furthermore, the devices and methods of the present invention do notrequire any manipulation of the collection site or solid support inorder to properly expose the captured matter to electromagneticradiation. This is in contrast to the existing methods of infra redspectroscopy, where the solid support, such as a membrane, must beremoved from its housing, the matter must be fixed on another support,such as a microscope slide, and then the support must be properlypositioned in a holder.

The devices of the present invention may also be disassembled to allowaccess to the matter capture medium, thus facilitating additional tests,if they are necessary. For example, after subjecting cells to infra redspectroscopy, the device may be opened, the membrane containing thecells may be removed, and the cells may be fixed on a microscope slide,or may be further processed, such as culturing or hemolyzing the cells,both of which process the cells for further testing.

According to another aspect of the present invention, the mattercollection apparatus may also include additional modules, removable orintegrated, for treating the fluid. For example, the fluid may betreated with a matter collection module, in combination with a debrisremoval module, a chromatography module, and assay module, orcombinations of these and other devices. These and other modules ortreatment protocols provide features which may be desirable toincorporate into a sample preparation apparatus according to theinvention.

New methodologies, such as immunocytochemistry and image analysis whichmay involve tagging target cells with chromophores, or light absorbanceor emitting probes, require preparations that are reproducible, fast,biohazard-free and inexpensive. The solid matter preparation techniquesof the present invention address the issues of non-uniform matterdensities, uneven matter distribution, and sample loss due to the numberof steps involved in the sample preparation. The preparations of thepresent invention result in an even distribution of solids that havesuperior morphology, improved visualization, and are readily positionedand available for light absorbance analysis without the need to furthermanipulate or prepare the sample.

For example, these methods have many advantages for conventionalmicrobiology and hematology. The collected cells are in a predeterminedarea easily accessible to a radiant light source and to a wavelengthabsorbance meter. Because cells are concentrated in a single layer, theyare almost always in one focal plane, thus eliminating or reducinginterference by other particles and virtually eliminating techniciantime and expertise in establishing a proper reading. The apparatuses ofthe present invention even permit the use of automated devices to detectand analyze any solid matter in a given population. It also permits adetailed analysis of the chemical composition of the matter.

The minimal matter overlap achieved in this process ensures that allmatter can be easily examined with little chance for critical solids tobe obscured by clumps of overlapping solids or debris.

The accompanying drawings show illustrative embodiments of the inventionfrom which these and other of the objectives, novel features andadvantages will be readily apparent.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a matter collection apparatus accordingto the present invention.

FIG. 2 is an exploded perspective view of a matter collection apparatusaccording to the, present invention.

FIG. 3 is a cross section of a collection element according to thepresent invention, including the collection site and an optical channel.

FIG. 4 is an exploded cross section view of a matter collectionapparatus according to the present invention.

FIG. 5 is a cross section of the outlet portion of a matter collectionapparatus showing the flow path of matter and fluid through thecollection element.

FIG. 6 is a cross section view of a syringe and matter collectionapparatus mounted on a collection cup.

FIG. 7 is a representation of a matter collection and detection systemaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises an apparatus having a housing, a mattercollection element disposed in the housing, and an optical channel forproviding communication between a radiant energy source and the mattercollection element.

The present invention also comprises an apparatus for preparing a samplefor exposure to a radiant energy source having a collection site throughwhich the absorbance pattern of the collected matter may be determined.

The present invention also includes collecting fluids, such asbiological, physiological, or environmental fluids, removing the desiredmatter from the fluid, without centrifugation, and diagnosing andtesting the matter by applying radiant energy to the matter in thedevice.

The present invention also includes a method for analyzing mattercomprising collecting matter on a collection element, and exposing thecollected matter to a radiant energy source. Preferably, the collectionstep and the exposure step occur within the same housing. A methodaccording to the invention may also include detecting and/or quantifyingthe absorbance of the radiant energy by the matter, may further includedetecting and/or identifying the matter by its characteristic absorbancepattern, and may include determining the composition of the collectedsample.

The present invention also includes an automated method for determiningthe presence and/or amount of a predetermined matter in a fluid.

The present invention also includes a kit having an assay module whichincludes a matter collection element according to the invention, a fluidspecimen cup, and a pump for inducing fluid flow through the assaymodule.

The present invention also includes a solid matter collection elementhaving a supported collection site and a channel through the support forexposing the collection site to electromagnetic radiation.

In a preferred embodiment of the invention, a collection module collectsand concentrates solids in a fluid in a predetermined position and at apredetermined thickness. In this way, the solids may be easily andreproducibly subjected to electromagnetic radiation in order to identifyand quantify the captured solid matter.

As used herein, fluid refers to any fluid for which it may be desirableto collect a component of the fluid for the purpose of establishing itsidentity or presence in the fluid. Typically, the component in the fluidwill be a solid matter, such as particulate matter. For example, thefluid may be air or gas, or a biological fluid, such as urine, and itmay be desirable to determine the presence of cancer cells or certainproteins in the biological fluid. In another example, it may bedesirable to evaluate the nature of contaminants, such as molecularcontaminants, in ultra-pure water used in the electronics industry.Other exemplary fluids include but are not limited to other body fluids,such as blood, spinal fluid, or amniotic fluid; bronchial lavage;sputum; fine needle aspirates; ground water; industrial processingfluids; electronic or medical dialysis fluids; to identify just a few.It is intended that the invention should not be limited by the type offluid being processed.

As used herein, solid matter refers to any substance in a fluid which iscapable of collection and evaluation using radiant energy sources.Exemplary matter includes, but is not limited to cells or cellfragments, proteins, molecules, polymers, rubbers, stabilizers,antioxidants, accelerators, silicones, alkyds, thiokols, paraffins,thermoplastics, bacteria, pesticides, and herbicides. Specific exemplarypolymeric matter include, but is not limited to polyethylene,polypropylene, polyisobutylene, polyacrylonitrile, polyethylene glycol,polyvinylchloride, polystyrene, polysulfide, polymethylmethacrylates,polyethyleneterephthalates, bisphenol A (a common environmentalcontaminant), ethyl cellulose, nitrocellulose, polyurethane, and nylon.Specific exemplary biological matter includes cancer cells, includingdistinguishing between metastatic and normal cancer cells; proteins,nucleic acids, antibodies, or the like. It is intended that theinvention should not be limited by the type of matter being processed.

As used herein, electromagnetic radiation refers to radiant energy whichcan be absorbed by solid matter, including but not limited to infra-redradiation, near infra-red radiation, the visible spectrum, and nearultraviolet radiation. For example, electromagnetic radiation may beused to determine structure, stereo-chemistry, types of additives,degree of degradation, presence of a copolymer, chain length,orientation, crystallinity, carbon-hydrogen stretching region,distinguishing between unsaturated and saturated carbon-hydrogenabsorptions, and the presence of individual molecules. Electromagneticradiation may also be used to determine the composition of a sample,e.g., the composition of a specific cell, protein, molecule, or polymer.It is intended that the invention includes the use of any type of energywhich can be used to identify and/or quantify solid matter.

As used herein, adapted for communication, communicating, or the likerefer to any means or methods for establishing fluid flow through thesystem, as are well known by practitioners in the art. A well knownstructure for establishing communication is a luer lock.

The systems and devices of the present invention are particularly suitedto fluids and matter in the fluids which are susceptible to radiantenergy evaluation. For example, cancer cells in urine may be identifiedby measuring the absorbance pattern after exposing the collected cellsto infra-red radiation.

An apparatus or assay module according to the invention includes ahousing, an inlet and an outlet defining at least one fluid flow paththrough the housing, and a collection element disposed in the housingacross a fluid flow path. In accordance with the invention, thecollection element includes a collection site. Although it may bevariously configured, as noted in more detail below, the module alsoincludes an optical channel that permits communication between a radiantenergy source, such as an infra-red spectrometer, the collection site,and an absorbance meter.

Exemplary methods and apparatuses according to the invention will now bedescribed in reference to the Figures.

FIG. 1 shows a typical module according to the invention, each modulehaving a housing 10, an inlet 11, an outlet 12, and a collection element13 (see FIG. 3).

As shown in FIGS. 2-4, an assay module or matter collection apparatuscomprises a housing 10 having an inlet 11 and an outlet 12. The housing10 defines a chamber 18, and the inlet 11 and the outlet 12 define atleast one fluid flow path through the housing 10. A collection element13 having a collection site 14 adapted to collect matter may bepositioned across a fluid flow path, the collection site 14communicating with the inlet 11. The collection element 13 within thematter collection apparatus is preferably adapted to define a flow pathhaving first and second branches, the first branch 21 extending throughthe collection site 14 and the second branch 22 bypassing the collectionsite 14.

In a preferred embodiment, the invention includes a collection element13 having a first porous medium 23, suitable for preventing the passageof matter therethrough, and a second porous medium 24, suitable forallowing fluid to pass therethrough. The second porous medium may or maynot be capable of removing particulate matter from the fluid, a designchoice according to the needs of a particular device. In a preferredembodiment, the first porous medium is suitable for capturing orcollecting solid matter, and even more preferably, capturing orcollecting solid matter in a uniform or single layer. A preferredembodiment also includes a second porous medium which is suitable as asupport for the first porous medium.

The collection element 13 also includes an optical channel 15b whichallows electromagnetic radiation to contact first porous medium 23without contacting second porous medium 24. Optical channel 15a, 15b,and 15c is any optical pathway through the module or housing whichallows the electromagnetic radiation to contact the solid matter. Asillustrated in FIG. 3, the optical channel 15b is a channel, hole, orthe like of any shape through the second porous medium, e.g., acentrally positioned annular hole.

The first porous medium and the second porous medium may be positionedin any fashion that functions as described herein. As one skilled in theart will recognize, the collection element may be variously configuredand positioned as needed to achieve a particular result. For example,the first and second porous media may be separate, spaced apart media;the two media can be laminated together; the first medium can beintegral with or removably engaged with the second porous medium; or thecollection element may comprise a zone of higher density which mimicsthe function of the first porous medium as described above, and zone oflower density which mimics the function of the second porous medium asdescribed above. Choice of these various configurations are well withinthe skill of practitioners in the art.

In a preferred embodiment of the invention, the first porous medium is apolycarbonate membrane and the second porous medium is a depth filter.

It should be noted that various types of first and second porous mediacan be used. U.S. Pat. No. 5,301,685 discloses several porous mediawhich may used in the present invention, and are hereby incorporated byreference. While a polycarbonate membrane is especially suitable for usein the solid matter collection apparatus of the present invention, anymembrane or septum which does not interfere with the electromagneticreading protocol is suitable. For example, polycarbonate membranes aswell as other porous membranes, such as cellulosic or nylon membranes,are also suitable because these membranes are compatible with infra redspectroscopy protocols. Exemplary media which may be used for fluidscreening include LEUCOSORB™, a leucocyte retention medium manufacturedby Pall BioSupport Division of Pall Corporation. Other membranesmanufactured and sold by the Pall Corporation are BIODYNE A™, anunmodified nylon with surface chemistry 50% amine and 50% carboxyl groupwhich has an isoelectric point of pH 6.5; BIODYNE B™, a surface-modifiednylon with surface chemistry characterized by a high density of strongcationic quaternary groups (the zeta potential is positive to pH>10);BIODYNE C™, a surface-modified nylon with surface chemistrycharacterized by a high density of anionic carboxyl groups (the zetapotential is negative to pH>3; and LOPRODYNE™, a low protein bindingnylon 66 membrane with a tightly controlled microporous structure havinghigh voids volume for rapid, efficient throughput of liquids andabsolute retention of microparticles designed for cell separation andbacterial cell immunoassays. In a preferred embodiment, the first porousmedium is a polycarbonate membrane suitable for preventing the passageof cells therethrough. Preferred polycarbonate membranes arecommercially available from Nucleopore, and are well known to thoseskilled in the art.

The collection element 13 may further include a depth filter as thesecond porous medium 24. The second porous medium permits fluid to passthrough by means of second fluid flow path 22, and may also function asa support for the first porous medium. The depth filter 24 may be madeof polypropylene or high density polyethylene POREX® porous plastics, aswell as any other material suitable for supporting the first porousmedium.

As shown in FIGS. 1 and 6, the first portion 16 or inlet 11 may includea portion configured as a connector and may be adapted to connect to acontainer or the like, or may be configured as a needle or cannula 32 orthe like. Second portion 17 or outlet 12 may include a portionconfigured as a connector and may be adapted to connect to a pump 30,e.g., a syringe, or the like.

The porous membrane preferably has a pore size from about 0.22 micronsto about 8 microns, more preferably from about 1 micron to about 6microns, most preferably about 2 microns, which allows it to trap cellswhich are more than 3 microns in size. The membrane, is suitable toallow fluid flow to pass therethrough while preventing the passage ofparticulate matter 20. The second porous medium is suitable for passingfluid therethrough and may also be capable of removing particulatematter from the fluid. The pore size of the second porous medium mayrange from about 5 microns to about 60 microns, preferably from about 15microns to about 45 microns, most preferably about 35 microns.

Another embodiment of the invention, illustrated in FIG. 6, includes anassay module or matter collection apparatus 10 mounted on a collectioncup 31, and includes a pump 30 for inducing fluid flow through thecollection module. The collection cup 31 may be a specimen cup or thelike, and/or the pump 30 may be a syringe or any other device forestablishing fluid flow. As shown in FIG. 6, either the collection cup31 or the collection module may include a cannula 32 or the like fordrawing fluid from the collection cup into the housing 10. In apreferred embodiment, the cannula includes perforations 33 at variouspositions along the cannula in order to draw fluid from different levelsin the collection cup 31.

The assay module housing 10 may be of any design which permits fluidflow through or across the collection element, e.g., a unitary housing.As shown in the Figures the assay module housing 10 is preferably a twopiece housing with a first detachable portion 16 and a second detachableportion 17, although any housing providing access to the collectionelement 13 is suitable.

Movement of a fluid through the system may be effected by maintaining apressure differential between a source of fluid and a destination of thefluid. Exemplary means of establishing this pressure differential may beby applying pressure to any part of the system on the inlet side of thehousing (e.g., the collection cup); applying a vacuum to any part of thesystem on the outlet side of the housing (e.g., the syringe); or anyform of pump, such as an autovial spunglass filter (manufactured byGenex Corporation); gravity head; or a flexible, collapsible container,such as a specimen container, which may be squeezed to force fluidthrough the matter collection apparatus and into the syringe. In apreferred embodiment of the invention, a syringe draws fluid from acollection cup through the housing.

As fluid passes through housing 10, the fluid flows through collectionsite 14 and collection element 13, as shown in FIG. 5. As one skilled inthe art will recognize, adjusting the pore size of the porous membraneand the porous depth filter in accordance with the type and/or size ofmatter to be collected permits the collection of the matter on thecollection site 14. In a preferred embodiment of the invention, the poresize is chosen so that a uniform layer of matter, preferably a monolayerof matter, is formed on the collection site.

One skilled in the art will also recognize that the depth of the layermay be adjusted to a predetermined or desirable depth. For example, fromabout 3 μm to about 40 μm or more has been shown to be effective, but itis intended that the invention should not be limited to a certain rangeof size or depth.

Once the uniform or monolayer of matter is formed, fluid flow along afirst flow path 21 is reduced in the center of the porous membrane andfluid flow along a second flow path 22 increases towards the edges ofthe collection element 13. While not intending to be restricted to anytheory of operation, it is believed that the increase in the fluid flowpath 22 may be due to the blockage of fluid flow path 21 by thecollected matter as it collects on the collection site 14. Matter in thesecond fluid flow path 22 will then bypass the collection site 14, thusmaintaining a substantially uniform layer or monolayer on collectionsite 14. The second fluid flow path 22 passes through an extended sidearea of the collection element 13, acts as a vent (with low resistanceto flow) and which prevents the piling up of matter.

The matter collection apparatus or module described above may be used incombination with other suitable filtration or treatment devices.Exemplary devices include other debris and/or assay devices or moduleswhich may be attached to housing 10. Typically, these additional moduleswill include a housing having an inlet and an outlet, and will include afiltration, assay, or detection element positioned across the fluid flowpath in the housing. For example, the apparatus may comprise a housingincluding inlet and outlet ports defining a flow path between the inletand the outlet; a filter positioned across the flow path; and a freelymovable chromatography/assay element, such as substrate beads,positioned on the outlet side of the filter. The chromatography/assayelement can freely mix with the matter in the fluid, capture the matter,and can then be assayed for the presence of the matter. Suitable devicesinclude those disclosed in U.S. Pat. Nos. 4,953,561; 5,224,489;5,016,644; 5,139,031; 5,301,685; 5,042,502; and 5,137,031, allincorporated herein by reference.

In accordance with a method of the present invention, matter iscollected on a collection element which includes an optical channel forexposing collected matter to electromagnetic radiation. After the matteris collected, the matter is analyzed by passing electromagneticradiation through the optical channel and then measuring the amountand/or type of absorbance.

For example, fluid may be drawn from a collection cup 31, throughhousing 10, allowing matter in the fluid to collect in a uniform layeror a monolayer on collection site 14. Optionally, additional fluid maybe drawn through the housing, or the same fluid may be drawn, thenreturned to collection cup 31, and then drawn again, as many times asdesirable. Once the matter is collected, the housing 10 may be placed ina holder or the like to properly position the optical channel in theelectromagnetic radiation beam, e.g., an infra red beam. The beam passesthrough the outlet 12 along optical channel 15a, 15b, and 15c. Inoptical channel 15b, the beam will contact matter collected on thecollection site 14. The collected matter absorbs a certain wavelength ofthe radiation, and this absorbance may be measured by placing anabsorption meter in the path of optical channel 15c.

A method according to the invention may also include processing thematter as noted above, and then transferring the matter to anothermedium for further analysis. For example, the present invention may alsoinclude transferring cells to a microscope slide. In contrast tocurrently available methods, the use of membrane filtration provides amethod of depositing cells or other matter evenly over a slide withminimal overlap. This allows for clear observation and optimaldiagnostic accuracy.

Included within the scope of the present invention is the production ofmultiple specimens from a single patient or source sample.

Also, captured microorganisms can be cultured in culture medium such asa standard petri dish. After the layer of cells has been collected inthe collection apparatus 10, fluid may be passed through the collectionsite 14 toward inlet 11 thereby transferring the microorganisms to thepetri dish.

In bacteria testing, the collection site 14 can be used for culturingwith a Qualture device (not shown) to determine the presence of specificbacteria colonies. The Qualture device is a plastic capsule containing afilter membrane and four nutrient pads of dehydrated, selective media.

The devices and methods of the present invention have a wide variety ofuses and applications, primarily because so many industries and so manyprocesses involve the separation of solid matter from a fluid followedby some type of examination of the solid matter. Exemplary industriesinclude food and beverage, pharmaceutical, medical and environmental(e.g., water, soil or air sampling), biology, microbiology, hematology,cytology, and pathology.

The devices and methods of the present invention are particularly usefulin any procedure which involves spectroscopy, the identification ofsolid matter such as compounds, molecules, cells, or proteins singly orin mixtures according to the matter's ability to absorb radiant energyat a specific wavelength. The devices and methods of the presentinvention are even more useful in any procedure which involves the studyof absorption patterns when substances are exposed to electromagneticradiation in the infra-red region of the spectrum, especially in thewavelength from about 2.5 μm to about 15 μm.

For example, in a hematological analysis, a drop of blood may beanalyzed for the presence and quantity of certain cell populations,since every cell has a certain signature profile under radiation such asinfra red radiation. For example, it may be desirable to determine theratio of lymphocytes to leukocytes, the presence and type of cancercells, protein level, or fat level.

In a variety of industries, it may be desirable to determine thepresence of a contaminant in a fluid such as air or water, e.g.,contaminants in drinking water, or bacteria in food and beverageprocessing plants. In environmental analysis, it may be desirable todetermine the presence, type, and amount of a certain contaminant, suchas estrogenic compounds, pesticides (DDT, heptachlor, and atrazine),aromatic hydrocarbons, and polychlorinated biphenyls. In both themedical and environmental fields it may be desirable to determine thepresence of breakdown products such as bisphenol-A, an ingredient inplastics.

The devices and methods of the present invention are also particularlyuseful when the matter may be tagged with a chromophore, a lightabsorbing or emitting probe, or any other visualization reagent. Forexample, cells and DNA may be analyzed by using a probe whichspecifically binds (indirectly or directly) with the matter of interest,and combining that probe with the first porous medium or by mixing theprobe with the fluid sample.

It should be clear that the device and method of the present inventionmay be used in a wide variety of industries, and for determining thepresence, amount, and composition of virtually any solid matter.

Although the present invention has been described in terms of aparticular preferred embodiments, it is not limited to thoseembodiments. Alternative embodiments, examples, and modifications whichwould still be encompassed by the invention may be made by those skilledin the art, particularly in light of the foregoing teachings. Therefore,the following claims are intended to cover any alternative embodiments,examples, modifications, or equivalents which may be included within thespirit and scope of the invention as defined by the claims.

I claim:
 1. A solid matter collection apparatus, comprising:a housinghaving an inlet and an outlet, said inlet and outlet defining at leastone fluid flow path through said housing; a solid matter collectionelement positioned in the housing across said path, said collectionelement having a collection site adapted for collecting solid matterfrom the fluid flow, and an optical channel through which radiant energyfrom a source of electromagnetic radiation is adapted for irradiatingthe collection site.
 2. The solid matter collection apparatus accordingto claim 1 wherein the collection element is adapted to define a flowpath having first and second branches, wherein the first branch extendsthrough the collection site and the second branch bypasses thecollection site.
 3. The solid matter collection apparatus according toclaim 2 wherein the collection site includes a first porous mediumcapable of preventing the passage of solid matter therethrough, saidporous medium being positioned across the optical channel.
 4. A solidmatter collection apparatus according to claim 3 wherein the collectionsite comprises a porous membrane.
 5. A system for collecting andanalyzing solid matter, comprising:source of electromagnetic radiation;a solid matter collection module comprising a housing and a collectionelement, the collection element having a collection site disposed in thehousing; and an absorbance meter; wherein said system includes anoptical pathway which passes from the source of the electromagneticradiation through the collection site to the absorbance meter.
 6. Thesystem according to claim 5 wherein the source of electromagneticradiation is a source of infra red radiation.
 7. A solid mattercollection element, comprising:a porous support having an opticalchannel through the porous support; and a collection site disposed onthe porous support and extending across the optical channel, saidcollection site being adapted for collecting solid matter at apredetermined density and position on the collection site, whereincollected matter will be in the path of electromagnetic radiationpassing through the optical channel.
 8. The solid matter collectionelement according to claim 7 wherein the porous support is a depthfilter.
 9. The solid matter collection element according to claim 7wherein the collection site comprises a membrane.
 10. The solid mattercollection element of claim 9 wherein the membrane has a pore size fromabout 0.3 microns to about 35 microns.
 11. A method of analyzing solidmatter in a fluid, comprising:screening the solid matter from the fluidand collecting the solid matter on a collection site; exposing collectedsolid matter to electromagnetic radiation passing through the collectionsite; and analyzing the solid matter exposed to the electromagneticradiation.
 12. The method according to claim 11, wherein said separatingsolid matter from the fluid and collecting the solid matter on thecollection site comprises passing the fluid through a collection elementhaving the collection site whereby solid matter in the fluid isseparated from the fluid and collected in a uniform layer on thecollection site.
 13. The method according to claim 11, wherein saidexposing the solid matter to electromagnetic radiation comprisesexposing the solid matter to infrared radiation.
 14. The methodaccording to claim 11, wherein said analyzing the solid matter exposedto the electromagnetic radiation comprises identifying the solid matterpresent on the collection site.
 15. The method according to claim 14,wherein identifying the solid matter present on the collection siteincludes quantifying the solid matter present.
 16. A method forpreparing solid matter for infra red spectroscopy, comprising:a) passinga fluid containing the solid matter through a collection apparatus thatincludes a collection element having a collection site adapted forcollecting the solid matter and an optical channel through thecollection element adapted for exposing the solid matter on thecollection site to infra red radiation; and b) depositing a uniformlayer of the solid matter on the collection site.
 17. The solid mattercollection apparatus according to claim 1 further comprising:avisualization reagent attached to the collection site.
 18. The methodaccording to claim 11 wherein analyzing the solid matter includesanalyzing for a visualization agent.